Pneumatic

[woody]

Pneumatic

2.75 inch bore 3.14 inches of stroke
Swept volume of 18.6 cubic inches
Pressure = 750 psi

Work that can be done by cylinder = 13,950lb-in

Divide by weight of bot to be moved 13,950/30 gives 465 inches or 38.75 feet.

A 50% fudge factor in practice seems to take into account losses etc in a flipper.........So 19 feet.

[wazio]

Pneumatic

19 holy moly thats great. I would be happy with even half of that! A question has been asked about how strong the arm support and cylinder mount will be... I think it should be fine.. I will have 2-3/4 AL supports that the arm and cylinder will mount to. Here is a pic: http://www.teamwazio.com/c-mount.jpgwww.teamwazio.com/c-mount.jpg

[woody]

Pneumatic

The arm / pivot looks good... not sure if your wheel mounts will take the strain of 4000lbs+ of thrust being applied to a 30lb weight.

It may be desirable to have the chassis flex enough to allow the base to touch the floor .....thus allowing the floor to take a good percentage of the load away from the wheels and mounts.....or perhaps squidgee tyres?

There is also going to be a fair ammount of bending moment applied to the chassis forward of the ram .......it might be a good idea to add a brace of some sort?
You could incorporate your Ali manifold and bottles as structural strength.

Just thoughts ......

[wazio]

Pneumatic

Put a new pic on the profile...

~Chad

[ewan]

Pneumatic

Wow, looks beefy. Any ideas yet on what youd use on the near vertical front tubes to get under your opponent?

(It is worth making sure that the weight isnt lifted too far forward - but that gives me an idea that if you have some wheely bars extend from the base plate out the front with rollers that only engage with the floor when the flipper is taking a load that might help spread the load of a somewhat painful theoretical 4000+lbs!)

[Guest]

Pneumatic

You pulled High Roller out of Robolympic 2007? :sad:
We were looking forward to seeing it fight Devastator, which is Marauder with a new name and owner (my brother).

[wazio]

Pneumatic

I might change the frame design a little and get rid of the base plate. I am messing with the CAD now... The arm is not done yet, it will have forks on the end of it...

High Roller will be at Robolympics (if it is done) I had to take it off the event in order to change something with the robots profile. No worries! :-)

~Chad

[wazio]

Pneumatic

I put a new pic up... And changed it up a little! Just gotta add the armor now.

~Chad

[Guest]

Pneumatic

Can someone draw me a picture to explain the differance between an open and closed pneumatic system with respect to combat robots? This was someones point in an argument we have been having about rules. I was told Marauder is a closed system pneumatic robot and therefore must follow the rules and the other robot was an open system robot and therefore the rules didnt appy to it.
I thought the differance was in an open you had 2/2 or 3/2 valves and a closed system used 5/3 valves. Am I wrong? Id prefer to be told Im wrong by people who know what they are talking about, because itll make a change to what I have to put up with the last week.

[woody]

Pneumatic

In an open circuit atmospheric air is pressurized, used in the pneumatic circuit and then exhausted back out into the atmosphere. This is one way that pneumatic circuits differ from hydraulic circuits. Hydraulic circuits are closed circuits. The same fluid is continually re-circulated within the circuit

Ive never heard of a closed pneumatic system .

[Guest]

Pneumatic

Ok, here are some proposed rule changes to make the offending robot leagel.
These rules apply to all open system robots. Closed system robots use the standard FRA or RFL rules.

Just to kick things of
-- Standard UN modified Soda stream bottles and valves and flow restrictors containing no more than the maximum rated weight of gas.

--The ram must have exhaust ports of XX area so at the normal working extension as assembled in the bot the ports are below the piston and can therefore vent the gas.

--The ram must be locked in the extended position whenever the gas bottle is fitted. It makes no difference if the bottle is full or empty. Apart from when it is in the arena. Or EO designated test area.

--A suitable low pressure blow off device, e.g. vac hose or spring-loaded valve installed at inlet of ram.

--Damage to CO2 bottle as for closed system rules.

--Mounting of CO2 bottle as for closed system rules.

---Electric operated CO2 valve must be spring loaded in off position .


I guess we get to remove the gauges and manual valves from our robot.

[Guest]

Pneumatic

Found another proposed rule.

--- I think for safety reasons with this class of pneumatics it would be worth specifying that the bottles must not be self filled (legally I think this is true anyway), but must be in the factory filled state.
This ensures that the burst discs and valve are new and safe, and that the bottle is not being filled while potentially damaged.

[leorcc]

Pneumatic

what is your definition of a closed system?

[woody]

Pneumatic

Daniel,
What is the supposed problem with Marauder?
Why do we need rule changes to make it legal?

Woody

[Guest]

Pneumatic

Here is a link to the thread on our forum where these rules are being discused on page 10;
http://robowars.org/forum/viewtopic.php?t=894http://robowars.org/forum/viewtopic.php?t=894

If you can be bothered reading through it you will see that the problem with Marauder is that it is apparently over-weight and that a Sydney based robot called Stealth that won a large compition in Melbourne at the start of the year wasnt built within the rules. Its CO2 supply, regulator(if it had one) and valve came from an old soda stream system, the tubing is vacume tubing from a car as is a seperate solenoid operated purge valve. I dont know where the ram came from but the builder has drilled holes into the cylinder close to its maximum extension to exauhst the gas in the ram at full extension. He believes this makes it safe to use parts not rated for the expected pressures because the system will never reach its maximum before venting.
This is what is being refered to as an open system while since Marauder will not vent the gas in the ram imediatly on reaching full extension it is being called a closed system. At least that is how I am interpreting it.